[Python-Dev] Possible wrong behavior of the dict?

[Florian Bruhin]

* Zaur Shibzukhov <szport at gmail.com> [2015-03-17 22:29:07 +0300]:
> Yes... But I expected that dict constructor will use `__getitem__`  or
> `items` method of MyDict instance  in order to retrieve items of the MyDict
> instance during construction of the dict instance... Instead it interpreted
> MyDict instance as the dict instance during construction of new dict.This
> exactly caused my confusion.

Subclassing builtins is always a recipe for trouble, because the C
implementation doesn't necessarily call your Python methods.

You should probably use collections.UserDict or
collections.abc.(Mutable)Mapping instead:

https://docs.python.org/3/library/collections.html#collections.UserDict
https://docs.python.org/3/library/collections.abc.html#collections.abc.Mapping

Florian

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